(1 point) Suppose that a particular industrial machine, when it is t years old, generates revenue at the rate R' (t) = 7125 - 12+² dollars per year and that operating and servicing costs accumulate at the rate C' (t) = 3300 + 9t² dollars per year. a. How many years pass before the profitability of the machine begins to decline? Answer: years. b. Compute the net profit generated by the machine over its useful lifetime. Answer: dollars.